(Ahlul Bayt News Agency) - The pilgrims moved from Mecca to nearby Mina by road, by train or on foot, the men wearing the seamless two-piece white garment tradition requires, the women covered up except for their faces, hands and feet.
In Mina, they will pray and rest before moving on to the Plain of Arafat on Monday for the climax of the pilgrimage rituals.
The recently constructed electric railway is scheduled to carry 400,000 of the pilgrims taking part in the world's largest annual gathering.
Saudi Arabia has deployed more than 100,000 troops to ensure the safety of the pilgrims and has warned it will tolerate no demonstrations or disturbances.
The oil-rich kingdom has also mobilized huge medical and civil defense resources to ensure the smooth movement of the pilgrims, around 1.4 million of whom come from abroad.
That figure is sharply down on last year's 1.75 million.
Riyadh has imposed a 20-percent cut this year on the quota for pilgrims coming from abroad.
It has also slashed the number of domestic pilgrims by half because of MERS virus fears and reduced capacity resulting from multi-billion-dollar construction work.
The fact that the kingdom accounts for the overwhelming majority of MERS cases reported around the world has raised concerns pilgrims could be infected and return to their homelands carrying the virus.
But the authorities have said they are optimistic the Hajj will pass without incident, given Muslims also go on lesser pilgrimages at other times of the year and there has been no problem.
This year's minor pilgrimage season, or Umrah, during the fasting month of Ramadan in July-August, passed off without any MERS outbreak even though millions of Muslims took part.
MERS is considered a deadlier but less transmissible form of the SARS virus that killed several hundred people in Asia in 2003.